We intend to serve as one of two clinical sites to evaluate digital mammography. The goal of this proposal is to test whether digital mammography is superior to film/screen mammography in the clinical setting. Digital mammography should increase the radiologist's ability to detect cancers. A study is being proposed to compare primarily acquired digital mammograms using the clinical digital mammography system being conducted at the University of Toronto Digital Mammography Group (UTDM) to film/screen mammograms. Patients will be selected from those undergoing mammography at the Thomas Jefferson University Hospital (TJUH) using a scheme to insure enough likely cancers as well as a spectrum of mammograms. Patients meeting study criteria will be asked to participate and, after informed consent, will have a second mammogram acquired digitally. The film/screen mammogram and digitally acquired mammogram will be interpreted by different radiologists with clinical information, but no access to the other study. The digital mammogram will have a third independent reading, adding the ability to manipulate the image with "soft copy" digital control. The digital examinations will be read again independently by radiologists in the University of North Carolina Digital Mammography Group (UNCDM). All data will be entered into computer protocols and analyzed together at the data coordinating center at the University of North Carolina. A correlated ROC analysis, and correlated regression analysis will be conducted. Digital film data will also feed into the Image Processing Study at the University of North Carolina, and the computer assisted diagnosis project organized by the University of Chicago Computer Aided Diagnosis Group (UCCAD). All these groups have agreed to collaborate as part of the National Digital Mammography Development Group under the coordination of the University of Toronto Administration Group (UTADM).